Air distribution outlets which receive air under pressure for heating and cooling purposes in automobiles and for clearing windshields of fog, ice and frost utilizing fluidic systems are well known in the art. In automobiles in particular, there has always been a design problem with such outlets which are, of course, a necessity both for the safe operation of the vehicle and for comfort of passengers. Typically the outlets are grills and/or adjustable vanes for directing air and recently, fluidic elements have been utilized in air outlet nozzles to control the direction of air flow and to provide for swept jet air flow into the passenger compartment of a vehicle and upon the windshield to clear same.
Impact modulators are well known in the art and usually comprise two input power streams or jets in which the streams impinge against one another coaxially in a common zone and the point of impact or impingement of the jets upon one another is projected in a given direction, and Moore U.S. Pat. No. 3,537,465 assigned to the assignee hereof is essentially a typical example of such a device. Kizilos et al. U.S. Pat. No. 3,367,581 discloses a fluid amplifier for performing a "jet-flap like function" and utilizes a cylindrical surface with a pair of jets projected along in oppositely tangential directions so that when the two streams meet on the surface, a single stream is formed which flows outward from the surface in a direction from a position on the cylindrical surface determined by the relative strenghts of the first and second lfuid streams so that control of the single stream by varying the relative strengths of the first and second streams is thus known in the art.
A basic object of the invention is to provide an improved air distribution and control system and method.
Another object of the present invention is to provide an air distribution system and method for automobiles which has no protrusions and no large openings on the occupant facing vertical surfaces.
According to the invention, an elongated air flow channel trough or groove is provided with a pair of nozzles at each end of the channel, trough or groove and connected to a source of air under pressure, each of the nozzles projecting an air jet along the axis of the trough or groove but in substantially opposite directions so that when the two air jets impact or impinge somewhere along a path defined by the trough or groove and where the two jets impact or impinge the air combines and is projected forwardly or outwardly in a direction normal to the channel, trough or groove and thus creat a virtual or invisible outlet. A further feature of the invention is that the velocity or strength of each jet is modulated to adjust the position of the virtual outlet. A further feature is the modulation of the velocity or strength of each jet in alternate and opposite directions to cause the virtual outlet and the projected air jet to move transversely of the axis of the groove or trough and thus sweep back and forth along a path defined by the trough or groove. The invention is particularly useful in connection with automobile instrument panel air control systems since there are no protrusions and it has a continuous clean appearance in the outlet and the two nozzles are substantially invisible and thus do not intrude upon the aesthetics of the instrument panel. The control of air issuing through the two opposing nozzles can be controlled by electrical means or by fluidic means. That is to say, the modulation of velocity of the air issuing through the two opposing nozzles can be controlled by electrically operated valves or by fluidically operated valves. The spot or oscillatory modes can be selected at will by the operator. As noted earlier, the motion fo the impact or impingement area of the two jets is controlled by the differential energy contained by the two supply jets or nozzles. This energy can, in turn, be controlled by a variety of ways such as a variable physical constriction of the flow area either by mechanical obstacle, iris or a gate valve or by electromechanically driven means or by a manually driven gate. The energy can also be controlled by a variable "apparent" constriction of the flow area by a fluidic means such as an air pressure control port transverse to the flow at the pair of nozzles or by pressurized control ports radial to the stream diameter causing rotational flow. In addition, the energy of the two jets can be controlled by bleeding one or the other supply nozzles by means of a mechanical valve, either manual or electromagnetically operated or by control port to variable pressure (vacuum) supply. Oscillation can be controlled by an electromagnetic valve or by fluidic means. By fluidic means it is intended to include cross coupling of each nozzle's supply pressure via a control tube, controlling nozzle control ports by a small pilot or fluidic oscillator. In the case of an automobile compartment, for example, the trough or groove can be formed of transparent plastic so that is can pass in front of or be an integral part of some of the instruments without in any way interfering with the visability.